The formation of pituitary hormones and active peptides from higher molecular weight precursors is dependent upon the action of specific endopeptidases. Degradation of hormones and peptide-factors controlling pituitary function is also dependent on the activity of such enzymes. The nature, however, of these enzymes is not known. The project is directed toward isolation and characterization of several pituitary endopeptidases, identified in our laboratory. The function of these enzymes in the interconversion and degradation of peptide hormones and biologically active peptides will be studied. The beta-lipotropin molecule will be used to study the possible function of these enzymes in the generation of active fragments from this prohomone. Specificity toward other biologically active peptides, such as beta-endorphin, luteinizing hormone-releasing hormone, somatostatin, oxytocin and vasopressin will be examined. Efforts will be directed toward detection of changes in the activity of these enzymes related to changes in the secretory status of the pituitary induced by commonly accepted procedures.